Respiratory

Question 1

Vd= ? (Physiologic Dead Space)

Answer 1

Vd=Vt * (Paco2 - Peco2) /Paco2

where Vt=tidal vol, Peco2=expired air Pco2, Paco2=arterial Pco2

Question 2

Ve= ? (minute ventilation)

Answer 2

Ve= Vt * RR

where RR=respiratory rate

Question 3

Va= ? (Alveolar ventilation)

Answer 3

Va=(Vt - Vd) * RR

where Vd=physiologic dead space (use another eq to calculate this)

Question 4

1 g Hb can bind how much O2?

Answer 4

1.34 mL O2

Question 5

For a normal person (15g/ dL HB), what is O2 binding capacity per dL?

Answer 5

20 mL O2 / dL

Question 6

O2 delivery to tissues = ?

Answer 6

O2 delivery = cardiac output * O2 CONTENT

Question 7

Diffusion of gas (Vgas) = ?

Answer 7

Vgas= A/t * Dk(P1-P2)

where A=area, T=thickness, Dk(P1-P2)~difference in partial pressures

Question 8

PAo2 (alveolar Po2) =?`

Answer 8

PAo2= 150 - (Paco2/0.8)
where Paco2=arterial Pco2. 150= Po2 in inspired air. 0.8=respiratory quotient calculated by CO2 produced/O2 consumed since more O2 is consumed than CO2 produced.